Determination of genetic diversity among Saccharina germplasm using ISSR and RAPD markers

Various species of genus Saccharina are economically important brown macroalgae cultivated in China. The genetic background of the conserved Saccharina germplasm was not clear. In this report, DNA-based molecular markers such as inter simple sequence repeats (ISSR) and random amplified polymorphic DNA (RAPD) were used to assess the genetic diversity and phylogenetic relationships among 48 Saccharina germplasms. A total of 50 ISSR and 50 RAPD primers were tested, of which only 33 polymorphic primers (17 ISSR and 16 RAPD) had an amplified clear and reproducible profile, and could be used. Seventeen ISSR primers yielded a total of 262 bands, of which 256 were polymorphic, and 15.06 polymorphic bands per primer were amplified from 48 kelp gametophytes. Sixteen RAPD primers produced 355 bands, of which 352 were polymorphic, and 22 polymorphic bands per primer were observed across 48 individuals. The simple matching coefficient of ISSR, RAPD and pooled ISSR and RAPD dendrograms ranged from 0.568 to 0.885, 0.670 to 0.873, and 0.667 to 0.862, revealing high genetic diversity. Based on the unweighted pair group method with the arithmetic averaging algorithm (UPGMA) cluster analysis and the principal components analysis (PCA) of ISSR data, the 48 gametophytes were divided into three main groups. The Mantel test revealed a similar polymorphism distribution pattern between ISSR and RAPD markers, the correlation coefficient r was 0.62, and the results indicated that both ISSR and RAPD markers were effective to assess the selected gametophytes, while matrix correlation of the ISSR marker system (r = 0.78) was better than that of the RAPD marker system (r = 0.64). Genetic analysis data from this study were helpful in understanding the genetic relationships among the selected 17 kelp varieties (or lines) and provided guidance for molecular-assisted selection for parental gametophytes of hybrid kelp breeding.     

DNA typing and genetic relations among populations of Kelussia odoratissima using ISSR and SRAP markers

Kelussia odoratissima is well known for its medicinal importance. It has been announced as an endangered species. Thus, examining the genetic variation and conservation of this plant is necessary. In the present study, inter simple sequence repeat (ISSR) and sequence-related amplified polymorphism (SRAP) molecular markers were employed for the first time to access the genetic diversity and relationships of 77 wild individual plants of K. odoratissima collected from seven populations in Central Zagros region of Iran. A total of 146 bands were amplified by 12 ISSR primers, of which 129 (87.80 %) were polymorphic, while 69 polymorphic bands (83.30 %) were observed among 86 bands amplified by 11 SRAP primers. Polymorphic information content (PIC = 0.32), resolving power (Rp = 7.80), and marker informativeness (MI = 3.48) generated by ISSR primers were higher than that of SRAP analysis (PIC = 0.30, Rp = 5.61, and MI = 1.88). The study indicated that ISSR were more effective than SRAP markers for assessing the degree of genetic variation of K. odoratissima. In both UPGMA dendrograms of ISSR and SRAP, in most cases, individuals from each population were clustered in various groups without clear separation, which demonstrates the high variability of this germplasm in Iran. UPGMA cluster analysis revealed inconsistencies in the clustering patterns, as the Mantel’s test between the dendrograms for ISSR and SRAP data indicated a poor fit for the ISSR and SRAP data types (r = 0.10). Besides, principal coordinate analysis results showed that the first three principal coordinates account for 65.57 % of the total variation and studied seven populations were separated from each other and placed into five groups. These results have an important implication for K. odoratissima germplasm characterization, improvement, and conservation.     

Efficiency of ISSR and RAPD markers in genetic divergence analysis and conservation management of Justicia adhatoda L., a medicinal plant

Genetic variation within and among population is the basis for survival of the population both in short and long term. Thus, studying the plant genetic diversity is essential for any conservation program. Indigenous medicinal plants like Justicia adhatoda L. which are facing high rate of depletion from the wild population need immediate attention. DNA-based dominant molecular marker techniques, random amplification of polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) were used to unravel the genetic variability and relationships across thirty-two wild accessions of J. adhatoda L., a valuable medicinal shrub widespread throughout the tropical regions of Southeast Asia. Amplification of genomic DNA using 38 primers (18 RAPD and 20 ISSR) yielded 434 products, of which 404 products were polymorphic revealing 93.11 % polymorphism. The average polymorphic information content value obtained with RAPD and ISSR markers was 0.25 and 0.24, respectively. Marker index (RAPD = 3.94; ISSR = 3.53) and resolving power (RAPD = 4.24; ISSR = 3.94) indicate that the RAPD markers were relatively more efficient than the ISSR assay revealing the genetic diversity of J. adhatoda. The Shannon diversity index obtained with RAPD and ISSR markers was 0.40 and 0.38, respectively. The similarity coefficient ranged from 0.26 to 0.89, 0.33 to 0.93 and 0.31 to 0.90 with RAPD, ISSR and combined UPGMA dendrogram, respectively. PCA derived on the basis of pooled data of both the markers illustrated that the first three principal coordinate components accounted 79.27 % of the genetic similarity variance. The mantel test between two Jaccard’s similarity matrices gave r = 0.901, showing the fit correlation between ISSR- and RAPD-based similarities. Based on the results, ex-situ methods may be the most suitable and efficient measure for long-term conservation.     

ISSR and RAPD Markers Assessed Genetic Variation of Aerides maculosum — an Epiphytic Orchid from Goa, India

Aerides maculosum Lindl is one of the most important orchids valued for its beautiful inflorescence/flowers. The present study aimed to understand the level of genetic variation among the populations of A. maculosum using RAPD and ISSR markers. Among the 35 primers tested, 13 RAPD and 6 ISSR primers were selected for the analysis. Total of 101 RAPD and 40 ISSR fragments were generated. High level of polymorphism was recorded in RAPD (90.45%) compared to ISSR (72.85 %). Nei’s average genetic identity values for different populations of A. maculosum- ranged from 0.465 to 0.762 (RAPD), while for ISSR it ranged from 0.475 to 0.975. The present study provides important insights about genetic variation in A. masculosum and may facilitates the conservation and management of this species.     

Genetic similarity among cultivars of Phyllostachys pubescens

Phyllostachys pubescens is the most important economic bamboo species in China, which grows widely in the South of China. There are more than ten cultivars in this species but their genetic relationship still remains unknown. We used both amplified fragment length polymorphism (AFLP) and inter-simple sequence repeat (ISSR) techniques to determine genetic similarity among ten cultivars of P. pubescens and two related species. Eight hundred and twenty seven bands, in which 495 are polymorphic, were detected using 15 pairs of AFLP primers whereas total 231 bands, in which 154 bands are polymorphic, were scored using 16 ISSR primers. Statistic analysis showed that the genetic similarity matrices obtained from these two sets of molecular markers had a significant correlation (R = 0.959, P = 0.013). The dendrogram generated with AFLP and ISSR markers could clearly genetically identify ten cultivars of P. pubescens that had high similarity with genetic distances ranging from 0.023 to 0.108, and could be divided into three groups based on their genetic variation and similarity. Our results suggest that these molecular markers are useful to genetically classify cultivars or varieties of a species, particularly a bamboo species.     

Interspecific genetic analysis of orchids in Brazil using molecular markers

Several species of Orchidaceae, one of the largest plant families, are considered endangered throughout South America and legal protection policies are needed so they can be preserved. Inter simple sequence repeats (ISSRs) markers are a potential tool to be used in the phylogenetic reconstruction of closely related species. In this study, we evaluate the polymorphic information content (PIC) and optimum number of ISSR markers (ONM) for five Laeliinae orchids in order to assess genetic diversity. The phylogenetic relationships between Cattleya granulosa, an endangered Brazilian orchid, and four other native Brazilian species (Brassavola tuberculata, Cattleya bicolor, Cattleya labiata and Cattleya schofieldiana) were analyzed for genetic diversity and differentiation. The 11 selected primers generated 166 unambiguous loci (PIC = 0.354; ONM = 156). Of the five studied species, C. bicolor exhibited the highest level of genetic diversity (H _E  = 0.219), while C. labiata exhibited the lowest level (H _E  = 0.132). The percentage of genetic variation among species (analysis of molecular variance) was 23.26 %. The principal component analysis (PCA) of ISSR data showed that unifoliate and bifoliolate species are genetically divergent. Additionally, PCA indicated a close relation between C. granulosa and C. schofieldiana, a species considered to be a variety of C. granulosa by many researchers. Thus, we conclude that ISSR genetic markers are effective in detecting genetic differentiation among orchid species.     

Comprehensive genetic discrimination of Leonurus cardiaca populations by AFLP,ISSR, RAPD and IRAP molecular markers

Leonurus cardiaca is well known for its medicinal importance. In this investigation, genotypic characterization of this species from six eco-geographical regions of Iran was evaluated by four molecular techniques (AFLP, RAPD, ISSR and IRAP). A total of 899 polymorphic fragments were detected by used molecular markers (AFLP = 356, RAPD = 325, ISSR = 113 and IRAP = 105) with an overall average polymorphism of 81.24 %. Genetic variation calculated using Shannon’s Information index (I) and Nei’s gene diversity index (H) showed high genetic diversity in studied germplasm. Also, analysis of molecular variance showed high genetic variation among (55 %) and within populations (45 %). UPGMA dendrogram constructed from combined data of molecular markers distinguished studied populations in accordance with the results obtained by each marker which all individuals were clearly differentiated into two major clusters. The correlation coefficients were statistically significant for all marker systems with the highest correlation between similarity matrixes of RAPD and ISSR markers (r = 0.82). The present results have an important implication for L. cardiaca germplasm characterization, improvement, and conservation. Furthermore, the characterized individuals exhibited a great deal of molecular variation and they seem to have a rich gene pool for breeding programs.     

Genetic variation within and among populations of a wild rice Oryza granulata from China detected by RAPD and ISSR markers

Genetic variation within and between five populations of Oryza granulata from two regions of China was investigated using RAPD (random amplified polymorphic DNA) and ISSR (inter-simple sequence repeat amplification) markers. Twenty RAPD primers used in this study amplified 199 reproducible bands with 61 (30.65%) polymorphic; and 12 ISSR primers amplified 113 bands with 52 (46.02%) polymorphic. Both RAPD and ISSR analyses revealed a low level of genetic diversity in wild populations of O. granulata. Furthermore, analysis of molecular variance (AMOVA) was used to apportion the variation within and between populations both within and between regions. As the RAPD markers revealed, 73.85% of the total genetic diversity resided between the two regions, whereas only 19.45% and 6.70% were present between populations within regions and within a population respectively. Similarly, it was shown by ISSR markers that a great amount of variation (49.26%) occurred between the two regions, with only 38.07% and 12.66% between populations within regions and within a population respectively. Both the results of a UPGMA cluster, based on Jaccard coefficients, and pairwise distance analysis agree with that of the AMOVA partition. This is the first report of the partitioning of genetic variability within and among populations of O. granulata at the DNA level, which is in general agreement with a recent study on the same species in China using allozyme analysis. Our results also indicated that the percentage of polymorphic bands (PPB) detected by ISSR is higher than that detected by RAPD. It seems that ISSR is superior to RAPD in terms of the polymorphism detected and the amplification reproducibility. Received: 29 March 2000 / Accepted: 15 May 2000     

Nuclear DNA assay of the wild endangered medicinal and aromatic Indian Himalayan Valeriana jatamansi germplasm with multiple DNA markers: implications for genetic enhancement,domestication and ex situ conservation

Population genetic analysis in the important endangered medicinal and aromatic plant species, Valeriana jatamansi, provided, first time, insights into the identification of novel sources of genetic variation as an aid for improvement and domestication, and for optimizing conservation strategies. The 75 genotypes of V. jatamansi were collected from 36 locations across northeast to northwest Indian Himalayas of ~1,000 km, harbouring variable climatic and ecological conditions and rugged rocky terrain. The known protocols for DNA extraction failed to yield quality DNA in good quantity. A new protocol was standardized for this purpose. All the three (RAPD, ISSR, AFLP) DNA markers were successful in detecting polymorphism in V. jatamansi genotypes, and the ISSR marker, vis-à-vis RAPD and AFLP markers, generated the highest level of polymorphism. The RAPD, ISSR and AFLP fingerprints with 23 and 15 primers and 8 primer combinations, respectively, revealed 85.8, 89.0 and 67.7 % polymorphism among 141, 91 and 37 genetic loci amplified from the 75 genotypes, respectively. The AMOVA analysis of AFLP (55.0, 8.3, 36.7 %), RAPD (57.4, 11.9, 30.6 %) and ISSR (76.0, 4.8, 19.1 %) data indicated that more variation existed in differences in genotypes within populations than between populations within a region and between regions, respectively. The present comprehensive input will assist in effective management and (or) devising conservation strategies of this important medicinal plant species. This study reports the start of a molecular biology programme targeting nuclear genome of V. jatamansi, the genetics of which is very little known.     

Population genetic diversity and divergence of the halobiotic herb Limonium sinense estimated by AFLP and ISSR, and implications for conservation

Limonium sinense is a halobiotic herb endemic to China that has been traditionally used for hundreds of years for its good restorative function. Genetic variation and population structure of this species were investigated by using amplified fragment length polymorphisms (AFLPs) and inter simple sequence repeats (ISSRs). A high level of genetic diversity was detected [AFLP: H _E = 0.284, percentage of polymorphic loci (PPL) = 92.68 %; ISSR: H _E = 0.257, PPL = 85.71 %] at the species level with POPGENE. Based on analysis of molecular variation (AMOVA), the among-population component accounted for 29.03 % (AFLP) and 28.81 % (ISSR) of the genetic variation, indicating that most of the genetic variation was between individuals within populations. The Shannon diversity index (I) was higher for AFLP (0.432) than for ISSR (0.395). Five main clusters were shown in the unweighted pair-group method with arithmetic mean (UPGMA) dendrogram created using TFPGA, consistent with the result of principal coordinate analysis using NTSYS. In situ conservation is advocated first. Keeping a stable environment for this halobiotic herb is necessary. For ex situ conservation, it is important to establish a germplasm bank. AFLP and ISSR markers were proved to be efficient tools in assessing the genetic variation among populations of L. sinense. The patterns of variation appeared to be consistent for these two marker systems, and they can be used for management of genetic structure, protection of the halobiotic plant, and conservation of germplasm.     

Genetic divergence and allelic-specificity in relation to expression of voltinism in silkworm using ISSR and RAPD fingerprinting

The silkworm B. mori is a multicellular organism revealing genetic resources which makes an ideal model for lepidoptera for the present investigation. With the objective of targeting distinctive markers for utilization in future breeding programmes, Bivoltine and Polyvoltine silkworm strains were used by inter-simple sequence repeats (ISSR) and random amplified polymorphic-DNA (RAPD) fingerprinting to detect their genetic versatility and volatility. Six ISSR primers generated 99 markers, of which 76.76% were found to be polymorphic with an average number of observed alleles (N _a) (1.86 ± 0.40), an effective number of alleles (N _e) (1.43 ± 0.30) as well as six RAPD primers that produced a total of 95 bands, developing 61.05% polymorphism with N _a (1.93 ± 0.51) and N _e (1.18 ± 0.30). The dendrogram produced by UPGMA analysis, based on Dice’s coefficient, clustered four races into two major groups which accurately segregated them according to their inheritance of voltinism. In this research, the ISSR markers were more accurate than the RAPD markers and ISSR also displayed better polymorphism. The outcome showed that the bivoltine strains exhibited higher allelic expressions with ISSR primers when compared to the polyvoltine strains. Despite exhibiting their unique race by certain DNA markers, most of the primers represented voltinism-specificity. Hence molecular marker amplification is a beneficial approach to reveal genetic divergence among closely related strains, and molecular characterization of phylogenetic relationships in addressing evolutionary evidences of individuals.     

Genetic variation,population structure and identification of yellow catfish, <Emphasis Type="Italic">Mystus nemurus</Emphasis> (C&;V) in Thailand using RAPD,ISSR and SCAR marker

Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers were used to investigate the genetic structure of four subpopulations of Mystus nemurus in Thailand. The 7 RAPD and 7 ISSR primers were selected. Of 83 total RAPD fragments, 80 (96.39%) were polymorphic loci, and of 81 total ISSR fragments, 75 (92.59%) were polymorphic loci. Genetic variation and genetic differentiation obtained from RAPD fragments or ISSR fragments showed similar results. Percentage of polymorphic loci (%P), observed number of alleles, effective number of alleles, Nei’s gene diversity (H) and Shannon’s information index revealed moderate to high level of genetic variations within each M. nemurus subpopulation and overall population. High levels of genetic differentiations were received from pairwise unbiased genetic distance (D) and coefficient of differentiation. Mantel test between D or gene flow and geographical distance showed a low to moderate correlation. Analysis of molecular variance indicated that variations among subpopulations were higher than those within subpopulations. The UPGMA dendrograms, based on RAPD and ISSR, showing the genetic relationship among subpopulations are grouped into three clusters; Songkhla (SK) subpopulation was separated from the other subpopulations. The candidate species-specific and subpopulation-specific RAPD fragments were sequenced and used to design sequence-characterized amplified region primers which distinguished M. nemurus from other species and divided SK subpopulation from the other subpopulations. The markers used in this study should be useful for breeding programs and future aquacultural development of this species in Thailand.     

Assessment of genetic diversity in Colletotrichum falcatum Went accessions based on RAPD and ISSR markers

Sugarcane is susceptible to red rot disease caused by phytopathogenic fungus Colletotrichum falcatum Went which ultimately affect the economy of farmers as well as sugar based industry. One of the various ways to control this devastating disease is to develop disease resistance sugarcane cultivar and this requires the complete understanding of genetic makeup of pathogen. Although South Gujarat is well known sugarcane cultivating area, less published data can be found about PCR-based genetic diversity in prevalent C. falcatum accessions. So, present investigation aims at finding molecular variation among the ten accessions of C. falcatum using RAPD and ISSR molecular markers. A total of 35 RAPD and 39 ISSR primers were screened across 10 C. falcatum accessions, of which 15 RAPD and 21 ISSR primers have showed consistent amplification. Statistics related to genetic variation were estimated using NTSYS-PC by means of Dice’s coefficient. The results revealed 80.6% and 68.07% polymorphism and similarity coefficient ranged from 0.43 to 0.91 and 0.73 to 0.93 in RPAD and ISSR analysis respectively. The dendrogram generated using RAPD, ISSR and combined RAPD-ISSR grouped accessions into different clusters which reveal considerable level molecular variation among the C. falcatum accessions. It is also evident from PCA plots that accessions are rather dispersed with tested marker systems indicating good genetic base. So, in nut shell, we found considerable genetic variation and relatedness within C. falcatum accessions collected from different areas of south Gujarat, India using RAPD and ISSR markers.     

ISSR and RAPD based evaluation of genetic fidelity and active ingredient analysis of regenerated plants of Picrorhiza kurroa

Genetic stability and phytochemical analysis of in vitro established plants of Picrorhiza kurroa Royle ex Benth, have been carried out. Random amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) markers were used to assess the genetic fidelity of tissue culture products including three adventitious shoots from three calli and 6 months old tissue culture raised plants growing in green house condition with mother plant. Apparent genetic variation was detected in the five types of plant materials. The percentage of polymorphic bands in the RAPD and ISSR analysis were 16.25 and 14.54 %, respectively. The genetic similarity was calculated on the basis of RAPD and ISSR data among the five types of plant materials and were ranged from 0.5 to 1.0 (mean 0.75) and 0.47 to 1.0 (mean 0.73), respectively. The similarity coefficient by both RAPD and ISSR analysis revealed that differences between tissue culture raised plants and mother plant was not remarkable, but notable differences were observed among three adventitious shoots regenerated from three calli. The phytochemical analysis of tissue culture raised products showed higher secondary metabolite (picrotin and picrotoxinin) content as compare to mother plant. The information gained on genetic stability/variability will be valuable for the large scale propagation and secondary metabolite production of P. kurroa.     

Genetic Diversity in Various Accessions of Pineapple [<Emphasis Type="Italic">Ananas comosus</Emphasis> (L.) Merr.] Using ISSR and SSR Markers

Inter simple sequence repeat (ISSR) and simple sequence repeat (SSR) markers were used to assess the genetic diversity of 36 pineapple accessions that were introduced from 10 countries/regions. Thirteen ISSR primers amplified 96 bands, of which 91 (93.65%) were polymorphic, whereas 20 SSR primers amplified 73 bands, of which 70 (96.50%) were polymorphic. Nei’s gene diversity (h = 0.28), Shannon’s information index (I = 0.43), and polymorphism information content (PIC = 0.29) generated using the SSR primers were higher than that with ISSR primers (h =  0.23, I = 0.37, PIC = 0.24), thereby suggesting that the SSR system is more efficient than the ISSR system in assessing genetic diversity in various pineapple accessions. Mean genetic similarities were 0.74, 0.61, and 0.69, as determined using ISSR, SSR, and combined ISSR/SSR, respectively. These results suggest that the genetic diversity among pineapple accessions is very high. We clustered the 36 pineapple accessions into three or five groups on the basis of the phylogenetic trees constructed based on the results of ISSR, SSR, and combined ISSR/SSR analyses using the unweighted pair-group with arithmetic averaging (UPGMA) method. The results of principal components analysis (PCA) also supported the UPGMA clustering. These results will be useful not only for the scientific conservation and management of pineapple germplasm but also for the improvement of the current pineapple breeding strategies.     

Population genetics of Ageratina adenophora using inter-simple sequence repeat (ISSR) molecular markers in China

Abstract

Understanding distribution and diversity of invasive weeds is essential for the development of efficient control measures against it. In the present study, inter-simple sequence repeat (ISSR) markers were used to assess the biogeographic relationships among populations of the invasive Crofton weed (Ageratina adenophora (Spreng.)) during 2004–2006 in China. A total of 100 ISSR primers with di-, tri-, tetra- and penta-nucleotide repeats were screened, from which 20 polymorphic and informative primers were selected. Amplification of the 20 primers generated a total of 479 polymorphic bands among the 64 weed populations, and a high level of genetic diversity (H _E = 0.1541 ± 0.0193) was detected in A. adenophora. Neighbor-joining (NJ) cluster analysis based on genetic distances among populations grouped the populations according to their geographical origin, i.e. (1) populations of southwestern Guizhou, (2) populations of Liangshan city in Sichuan, (3) populations of western Guizhou, (4) Guangxi populations plus Chongqing populations, (5) populations of southern Yunnan, and (6) populations of Yangtze River Valleys in Sichuan plus populations of western Yunnan. A significant positive correlation between geographical and genetic distance was detected by the Mantel test (r = 0.183, p = 0.0012). Based on the divergence relationships revealed by ISSR markers, it was assumed that A. adenophora mainly dispersed through wind and water in China.     

Evaluation of genetic diversity amongst <Emphasis Type="Italic">Descurainia sophia</Emphasis> L. genotypes by inter-simple sequence repeat (ISSR) marker

Descurainia sophia is a valuable medicinal plant in family of Brassicaceae. To determine the range of diversity amongst D. sophia in Iran, 32 naturally distributed plants belonging to six natural populations of the Iranian plateau were investigated by inter-simple sequence repeat (ISSR) markers. The average percentage of polymorphism produced by 12 ISSR primers was 86 %. The PIC values for primers ranged from 0.22 to 0.40 and Rp values ranged between 6.5 and 19.9. The relative genetic diversity of the populations was not high (Gst =0.32). However, the value of gene flow revealed by the ISSR marker was high (Nm = 1.03). UPGMA clustering method based on Jaccard similarity coefficient grouped the genotypes into two major clusters. Graph results from Neighbor-Net Network generated after a 1000 bootstrap test using Jaccard coefficient, and STRUCTURE analysis confirmed the UPGMA clustering. The first three PCAs represented 57.31 % of the total variation. The high levels of genetic diversity were observed within populations, which is useful in breeding and conservation programs. ISSR is found to be an eligible marker to study genetic diversity of D. sophia.     

Genetic diversity of <Emphasis Type="Italic">Opuntia</Emphasis> spp. varieties assessed by classical marker tools (RAPD and ISSR)

Opuntia, commonly named “nopal” in Mexico, is an important crop for its agronomical, economical, ecological and cultural value. Furthermore, it is known for its taxonomic complexity. In this paper, we report the genetic variability of 52 Opuntia cultivars with agronomic and economic importance, classified into 12 different species using random amplified polymorphic DNA (RAPD) and inter-simple sequence repeats (ISSR) markers. Ten primers, five for each marker type, were selected to assess their ability to detect polymorphisms in this plant accesions/varieties. Both marker systems generated a total of 307 bands, of which 50.8 % were polymorphic with an average of 15.6 polymorphic bands per primer. Thus, we assume that Mexican Opuntia varieties present broad genetic variation. Based on percentage of polymorphic bands; resolving power; polymorphic information content; and Marker Index, the K-12 (RAPD) and IS-06 (ISSR) primers were the most informative ones. Clusters obtained from RAPD, ISSR and a combination of both data sets did not match the actual taxonomic classification. On the other hand, the putative varieties currently classified in the same species were not located in the same cluster. Besides, the varieties included in O. ficus-indica, O. albicarpa and O. megacantha showed broad variation but were not well defined into separate clades; these cultivars possibly have common ancestry. The results presented here support our hypothesis about the existence of a smaller number of Opuntia species in accordance with those currently described, but with high intraspecific genetic variation.     

Molecular genetic diversity of Satureja bachtiarica

Fifty-seven genotypes from eight population of Satureja bachtiarica was evaluated using fifteen ISSR and eleven RAPD markers. DNA profiling using RAPD primers amplified 84 loci, among which 81 were polymorphic with an average of 7.36 polymorphic fragments per locus. Also, using RAPD markers maximum and minimum polymorphic bands observed for Semyrom (77.38 %) and Farsan (40.48 %) populations, respectively. Semyrom population recorded the highest unbiased expected heterozygosity (0.259) and Shannon’s Indices (0.38). While, the lowest values of unbiased expected heterozygosity (0.172) and Shannon’s Index (0.245) were recorded for Eghlid and Farsan populations, respectively. On the other hand, ISSR primers produced 136 bands, from which 134 were polymorphic with an average of 9.06 polymorphic fragments per primer (98.52 %). The ISSR markers evaluation revealed that maximum and minimum polymorphic bands observed for Semyrom (66.18 %) and Farsan (31.62 %), respectively. Shahrekorud population recorded the highest unbiased expected heterozygosity (0.211) and Shannon’s Indices (0.301). While, the lowest value of unbiased expected heterozygosity (0.175) observed for Farsan and Yazd populations and the lowest Shannon’s Index (0.191) recorded by Farsan population. The overall results of the study revealed that both ISSR and RAPD markers were effective for evaluation of genetic variation of S. bachtiarica.     

辣椒种质遗传多样性的RAPD和ISSR及其表型数据分析

用RAPDI、SSR分子标记及28个表型性状数据对辣椒属5个栽培种的13份材料进行了分析,结果表明:23条RAPD引物共扩增出209条带,平均每个引物扩增出9.09条,多态性位点比率为83.73%;16条ISSR引物共扩增出94条带,平均每个引物扩增出5.88条,多态性位点比率为79.79%.与RAPD相比,ISSR标记检测到的有效等位基因数(Ne)及Shannon多样性指数(I)、遗传离散度(Ht)和遗传分化系数(Gst)等遗传多样性参数都较大,多态性位点比例在亲缘关系较近的一年生辣椒(Capsicum annuum)种内较高,说明ISSR有更高的多态性检测效率,并且适合亲缘关系较近的种群间遗传多样性分析.基于RAPDI、SSR的聚类与基于表型数据的聚类之间存在极显著正相关,且都能将C.annuum与其它栽培种区分开来.